Corrugated structure



Jn-4,1938, A. L. SPAFFQRD 2,104,060

CORRUGATED STRUCTURE Filed oct. 1e, 19.31 3 sheets-snee: 1

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' Jan. 4, 1938. A SPAFFORD 2,104,060

\ coRRU-GATED STRUCTURE y Filed oct. 1e, 1951 s sheets-sheet 2 @La[yum/l.

Jan. 4, 1938. A. sAFFoRD l 2,1104060 y CRBUGATED STRUCTURE l Filed Oct.16, 1951 3 Sheets-*Sheet 3 Patented Jaa. 4, 193s PATENT. or-:FICE

. alliantA CORRUGATED STRUCTURE Allen L. Spafford, Cloquetltiinn.,assignor to Wood. ConversionV Company, Cloqnet, Minn., a corporation ofDelaware Y Application October 16, 1931, Serial No. 569,198

'I'he present invention relates to corrugated structures or sheets.represented by the so-called andf well known corrugated board' andcorrugated paper- Ordinary corrugated forms are made from paper andcomprise essentially a corrugated sheet, which maybe used alone, orwhich may be adhesively united to a singlefacing, or secured betweentwoffacings. It is made to have rigidity and in certain formsnon-flexibility. The applications of it in use are largely those whichtake advantage of its rigidity, its non-flexibility, and its greatstrength for a light-Weight cheapmaterial.

Some of its chief disadvantages in such uses are its fragility when`bent or broken', its brittleness as a structure, and its ease ofpuncturing. Another defect in commonl forms is the fact that it is notwater-proof. Aside from its desirable properties for structures, it hasa high heat insulation value, particularly where it is used in pileformation. It also has sound deadening properties and it may be used forthis property. In many forms uof insulatiomfor lheat and sound, strengthand rigidity are not essential, and in other forms flexibility,toughness, elasticity, waterproofness and other qualities are verydesirable.

'e' vThe present invention aims to provide corrugated structures whichmay be more exible than ordinary forms, and more elastic, and which maybe water-proofed, and tough. `m

One object of the invention is to use in corrugated structures,a shcetoflelastic material, or tough material, or highly flexible material,insuch a way that these properties are imparted to the corrugatedstructure.

A particularI object is to regulate and control the properties by therelative arrangement of the corrugations and the component parts of thestructural element or elements. Another object is to use in a corrugatedstructure one, two, or three elastic sheets, -suchaa crepedpaper havingparallel c re'ping, and to ari range the crepix'ig lines either inparallel, or transverse-or otherwise, to the` corrugations to impartdiilerent degrees or to give particular dif rectional Aproperties to thestructure.

w of one,'twov or three universally elastic sheets,-

suclias diagonally and doubly crepedsheets in a -angles tothe^corrugations.f 1

Still another object of the .invention is the use Y paises schemaeema"(c1. 15a-L55) such-as asphalted, or creped asphalted paper in acorrugated structure. v Various other objects and advantages of the'invention will become .apparent from the following description of theinvention and uses of the forms and structures which are shown in theaccompanying drawings in which:

Fig. 1 represents a fragmentary section of a corrugated sheet having'creping lines parallel with the corrugation.` 10

Fig. 2 represents acorrugated sheet having creping lines at right anglesto the corrugations.

Fig. 3 represents a curved corrugated sheet having creping linestransverse tothe corrugaf tions and represents the sheet of Fig. 2deformed 16. into the shape illustrated.

Fig. 4 represents a 4corrugated sheet having creping in two directionsat right angles to each other 'and at 45 with the corrugations.

Fig. 5 represents a-modied form of corrugated 2o y sheet in which thecorrugations are sharp like accordion pleats.

Figs. 6, 7 and 8 represent respectively the corrugatedsheets of Flgs..1,2 and 4 faced with a plane liner. 1

Fig. 9 represents acorrugated sheet like that of Fig. 4 faced with vtwoliners of diagonally creped sheets. 4 Fig. 10 is a schematic anddiagrammatic representation of a single faced corrugated. sheet 30including designations by illustration of the types of materials andarrangement thereof which may .be used in combination .in the structure,including particularly as the corrugated sheet a creped form. .J l 35Fig. 11 is a schematic and diagrammatic `-representation of a. doublyfaced corrugated sheet including designations by illustration of thetypes of materials and arrangement thereof which may be used inlcombination in thestructure, includ- 40 ing particularly as the'corrugated sheet a creped` Fig. 12 represents a single faced corrugatedplane sheet, the facing being creped and at right Fig. 13 represents a',single faced corrugated plane sheet; thei'acing being creped .parallelto 4the .corrugationa Fig. 14 represents a doubly faced 'plane corru.

gated sheet having` one racing which is ereped so" atright'anglestothecorrugations.

Fig'. 15 represents a double faced .planecorrugated'sheethavingoneifaoecrepedparallelto the corrugations.

sentation of a single faced corrugated sheet including designationsv byillustration of the types of materials and arrangement thereof which maybe used in combination in the structure, including particularly as thecorrugated sheet a plane sheet.

Fig. 17 is a schematic and diagrammatic representation of a double facedcorrugated sheet including designations by illustration of the types ofmaterials and the arrangement thereof which maybe used in combination inthe structure, including particularly as the corrugated sheet a plane4sheet.

In explaining the nature of. the invention it is deemed expedient toillustrate specifically only a few of the forms in which the inventionmay be embodied, for the -reason that a very large number of otherstructures may be built up from different combinations of the variouselemental forms. The properties of the built up structures may becontrolled by the choice of different forms of the present invention. Inthe accompanying descriptions of the various illustrated forms, briefmention is madeA of various uses for which aparticular form may beemployed. In this way it is made easier to explain the advantage andspecific merit of one form over other forms.

In practicing the invention the conventional.

relation of corrugated sheet to one or two liners or facings ismaintained. In place of one,. two, or three' plane sheets, as of paper,in such structures I use in various combinations at least one elasticsheet, such as, a creped sheet of paper. Various combinationsof planeand elastic sheets may be used. I may use an elastic sheet which hasunidirectional elasticity, such as a sheet of paper creped with parallelcreping lines. I may use a sheet universally elastic, such as one havingmaximum elasticity in two directions, and hence elasticity in alldirections, such as a sheet which is creped in two directions. Such asheet is exemplifed by paper having one set of parallel crepinglines,crossed' by another'set of parallel creping lines, preferably at rightangles to the ilrst set, diagonally to a web of paper. Such a paper iselastic in all directions.

' -The two types of creped paper may be watercreped, or may be crepedwith asphalt or other heat-plastic adhesive, generally described in theU. S. patents to Rowe Nos. 1,628,515 and 1,782,767. Such sheets arewater-proof and tough. They may be coated with asphalt, or other crepingagent on only one side, and be uncoated on the other side. The sheetsmay be coated on two sides, so that both sides are water-proofed, as byasphalt or'other agents, as described in my copending U. S.- applicationSerial No. 557,564,

led August 17, 1931, noW U. S. Patent No. 2,075,

835, issued April 6, 1937*. Both the singly creped paper vand the doublycreped paper may have either one side or both sideswater-proofed.

he plane sheet which I may use in the various forms of this inventionmay also be waterproofed on one or both sides. It may be a duplex sheet,such as two paper sheets cemented together with a water-proofing agentlike asphalt.

None of the above materials per se is new, or embody this invention, buteach may be an element in combination with itself or with another formin various embodiments of this invention.

The varous combinations which are' contem-` plated as falling Withinthis invention using the specific elastic forms and plane sheets ofmaterial illustratedin the drawings number well over fifty. In order notto` burden the drawings and the description,I unnecessarily with all thespecific forms, 'the disclosure is made somewhat diagrammatic and thedescription is schematic. The following keys to the combinations willreadily ex- 'plain the description and thev drawngs. The ilal elasticityand flexibility. The flexibility is less apparent as a uni-directionalquality than is the elasticity. Because of its uni-directional structureand properties it may be used at various angles to the corrugations. Ihave illustrated its use'in parallel with them and at right angles tothem. In designating these two specic uses, the-single` material hasbeen designated by two distinct indicia, according to the use, and itmay be considered, merely forl convenience in making combinations, astwo materals. In fact it may be two materials when a web of it isconsidered, as in a roll, as distinguished from a fragment. When it iscreped across the direction of formation it is a different material thanwhen it is creped with the direction of formation. It is one materialcommercially, or in manufacture, when the parallel. creping extendsparallel with the length of the web of commerce, and another when theparallel creping ,extends parallel with-the Awidth of the web.

In designating any one material several indicia are used according toits position in the structure. Y Any one of the materials may be afacing or may be a corrugated sheet. When one is a corrugated sheet itis indicated by a letter from the middle of the alphabet. When one is afacing in a structure having only one facing, it is designated by .aletter at the beginning of the alphabet. When one is a second facing itis designated by a letter near the end of the alphabet. The indicia are:

With this explanation of the drawings and of the key to the description,the structures and creped sheet is sufcient to sustain the corrugations,and that the variations or treatment of a plane sheet are proportionedto secure this. Such a -sheet is `particularly useful in combinations.It Imay be adhesively unitedto lother sheets as will be hereinafterdisclosed. It may be piled between separator sheets, or piled crosswiseon each other` ina package or laminated sheet which may 'be flexed orstretched. K Because of the creping l the stretching. may be in thecreping and not wholly in the corrugations. It may be used as awrapping,.having less rigidity than the similar prior art structure'iofplane paper. Its greater -exibility' permits its use as a combinationcorrugated vand plane flexible wrapper. Whencreped ber of the characterdescribed for Fig. l, is corrugated at Il transversely of the crepingI5. It has a distinctive property that it can be curved as shown in Fig.3 without loss of its corrugated form. The crepings permit unequalstretching of the sheet. The curvature may be in both directions in asingle sheet. A curved article may be wrapped with such a sheet and itmay be used in a package or blanket of insulation which may be made inirregular shape. `A sheet curved like -that lin Fig. 3 may be cementedto one or two liners to form of corrugations.

make a curved or non-planar section in a corrugated sheet. It mayreadily be stretched. It is very tough and has a exibility'andelasticity not found in simplecorrugated sheets of plane paper. i InFig. 4- a universally elastic sheet such as diagonally creped paper I'Iis corrugated at I8. This sheet combines all the properties of thesheets of Figs. 1 and 2 and has-in addition greater elasticity andflexibility.

In Fig. 5 I show a conventional representation vof a'sheet I9 withaccordion pleating 20 in a sheet whichgives substantially the sameladvantages as the conventional curved or sinuous It has an additionaladr vantage of being more easily compacted when squeezing of it' isdesirable. In this description I aim' to include within the broad termcorrugated,

the 'pleated form as well as the-.sinuous form. However, it is vto be'appreciated that where an adhesive is used to secure a liner, thesinuous form offers more area for adhesive than does the v pleated form.The sheet I9 4may therefore be made into any elastic sheetV form, suchas I have I described.

In Fig. 6 a creped sheet M (corrugated) such as shown in Fig. 1 issecured to a single facing of plane sheet A such as paper. The planesheet A may be water-proofed. Adhesive isindicated at 22.- This may besodium silicate, casein, starch or animal glue, orVV a water-proofcement like asphalt. The sheet MA has great flexibility, The

corrugated side is tougher and more resistant to puncture or tear thanis the conventional similar form made from two plane papers. Where thesheet M is asphalt creped paper it is a waterproofed one. The asphalt ofcreping may be on either side, or asphalt may be on both sides.

" It is particularly useful where it is desired inamaking a flexible ortough flange or area as previously suggested, either in a single sheetof it, or in a' pile of them.

vIn Fig. 7 a sheet N (Fig. 2) -is united with a plane sheet A as afacing. The creping is across the corrugations. I'his sheet NA is highlyflexible across the corrugations without breaking the structure. It maybe wrapped in a curve of short radius. An'edge flange crossing thecorrugations may be formed by compressing the edge, andthe flange ishighly tough and flexible, so that it may be folded or rolled into amounting strip.

l yformed and used in ways similar to structures MA and NA with Aall theadvantages ofthe latter and'with increased degree, and wlthadditionaladvantages.-

as having a plane corrugated sheet Fig. 9 is representative of atwo-faced sheet. It is illustrated specifically as made of three sheets,

all universally elastic', such as the diagonally creped paper previouslydescribed, and its combnation is DOZ. It stretches and ilexes easily inall directions. The sheets employed may be altered to other forms aswill appear hereinafter. The diagonally creped asphalted sheets arepreferred because .of their extremely tough, flexible and water-proofcharacter.

vIn Fig. 10 a diagrammatic illustration of one phase of the invention isshown, relating to a single-faced corrugated sheet. A corrugated sheetmay be made of the materials selected In Fig. ll a two-faced corrugatedstructure is v sho-wn diagrammatically'comprising a corrugated sheet 28,one facing 29, and a second facing 30. The sheet 28 may be selected fromthe list M, N and O. The sheet 29 may be selected from the list A, B, Cand D. The sheet 30 may be selected from the list W, X, Y and Z. This isall illustrated' in the drawings. The following -combinations varecontemplated: (either W, or X or Y or Z) (either, M, or N, or O) (eitherA,or B, or C,`or D). Of these the combination ZOD has been specificallydescribed with reference to Fig. 9.

' The invention is not limited to changes in the prior art from thecorrugated plane sheet, and the latter may be used in combination withelastic facings. Fon example, I have made the combinations PC (Fig. 12),PB (Fig. 13), CPW (Fig. 14) and BPW (Fig. l5) In all of these sheets Cand B may be of creped asphalted paper, watervproofed on one or bothsides as desired. Such forms are suitable for making water-proofcartons. The creped paper is preferably used on'the' outside of acarton, to resist water, and to provide a tough surface which is diicultto break, tear or puncture. vRigidity and flexibility may be' providedin varying degrees by the arrangement of the parts.' Forms PC and PBhave great flexibility along the corrugations, and it is more pronouncedin PB. For cartons, where less flexibility is desirable, form PC ispreferred. 4The flexibility and toughness is used advantageously ininsulation structures as heretofore described. Where less flexibility isdesired in a tough surfaced structure form CPW (Fig. i4) is preferred.Form BPW' (Fig, l5) is extremely flexible along the corrugations becauseof the elasticity in the creped sheet B. This form may be wrapped abouta curved surface with sheet W against the surface. Stretching in sheet Bprevents rupture of the structure.

Various other combinations are contemplated as illustrateddiagrammatically in Fig. 16 and Fig. 17. In Fig. 16 a single facedstructure is illustra'ted as having a plane corrugated sheet 32 4 Y beendescribed in reference to Figs. 13 and 12x-e- In Fig. 8 the structure OAis formed, or may be i spectively.

In Fig.

35,.one facing 38, and a 'second facing 31. The sheet 36 may be selectedfrom the .list B, C andD.

17 memo-faced structure is illustrated, f

'rne'sheet u 7 5 may be selected from the 11st x, Y and z.

other functional properties;

The combinations maybe: (either B, or C. or D) (P) (either X, or Y, orZ). Of these combinations BPW has been described in reference to Fig.15, and CPW in reference to Fig. 14.

It is to be understood that the direction of elasticity in a sheet inthe structure has a' relation to the direction of corrugations. Forexample where parallel corrugations and a set of parallel creping linescross on a diagonal, the elasticity from the creping is impartedbothalong and across the corrugations, whether the creping lines and thecorrugatons be in one sheet, or in different sheets in a compositestructure. Thus in Fig. 4 but one set of the creping lines diagonal tothe corrugations makes the sheet elastic in the direction of the ridgesand valleys of the corrugations.

From the foregoing it will be understood that the present inventioncontemplates a corrugated structure, of sheet material, such as paper,which includes an elastic sheet, such as a creped sheet havinguni-directional or universal elasticity and The elastic sheet may be oneor more of the essential parts of corrugated structures, and all suchparts may be elastic sheets. In the accompanying claims the invention isdeiined broadly to include all the forms illustrated, described orsuggested, and such modiiications thereof as fall within the scope ofthe invention as deiined by the claims.

Reference is made to applicants copending divisional application SerialNo. 157,817, illed August 7, 1937, for matter disclosed herein and 'notspeciiicallyA claimed.

I claim:

1. A corrugated sheet which is initially creped in two crossingdirections.

2. A composite structure comprising essentially a sheet having parallelcorrugations, which sheet is creped with lines diagonal to saidcorrugations to provide stretch in the direction of the lines ofvcorrugation, and a ilexible facing sheet secured thereto, said compositecorrugated structure being ilexible transversely of corrugation.

3. A composite structure consisting of a sheet having parallelcorrugations, which sheet is creped with lines diagonal to'saidcorrugations to provide stretch in the direction of the lines of.corrugatlon, and a dexible facing sheet secured to each face of saidcorrugated sheet, one of said the direction of the lines ofcorrugation.=

4. `A composite structure consisting of a sheet having parallelcorrugations, which sheet is creped with lines diagonal to saidcorrugations to provide stretch in the direction of the lines ofcorrugation, and a ilexibie facing sheet 'secured to facing sheets beingcreped to provide stretch `in each side of said corrugated sheet. eachfacing' sheet being creped to provide-stretch in the direction of thelines of corrugation.

ALLEN L sPAFman.

